The present invention relates to a method of manufacturing fibre reinforced metal components, particularly fibre reinforced metal rings, cylinders and discs.
The ideal arrangement for a fibre reinforced metal ring, or disc, is to arrange the fibers circumferentially such that they extend continuously without breaks in a fully dense metal matrix. This is difficult to achieve because a certain amount of movement is required in practice to achieve good diffusion bonding, and density, between the layers of fibers. The fibers used to reinforce the metal matrix are ceramic, and ceramic fibers have very low extension to failure values, typically 1%. On consolidation using radial pressure from the inside surface of the ring the continuous ceramic fibers are placed under high tensile stress resulting in filament breakage and loss of structural integrity. On consolidation using redial pressure from the outer surface of the ring, the continuous ceramic fibers are buckled which reduces structural integrity. On consolidation using radial pressure from both the inside and outside surfaces of the ring, the continuous ceramic fibers either break under high tensile stress for the radially inner layers of ceramic fibers or buckle for the radially outer layers of ceramic fibers. This resulting fibre reinforced metal ring therefore contains many random fibre breaks and thus the fibre reinforced metal ring has unknown levels of mechanical properties.
In one known method of manufacturing a fibre reinforced metal ring, as disclosed in UK Patent Application No. GB216S032A, a filament is wound spirally in a plane with matrix material between the turns of the spiral. The spiral is positioned between discs of matrix mate rial, and is then pressed axially to consolidate the ring structure. This method produces little or no breaking of the fibers, however it is a laborious method.
In a further known method of manufacturing a fibre reinforced metal ring, as disclosed in UK Patent Application No. GB2078338A, a metal matrix tape, which has reinforcing fibers, is wound onto a mandrel and then inserted into a metal shaft. The fibers are arranged generally axially of the shaft. The assembly is pressed to consolidate the ring structure. This method does not have the ideal arrangement of fibers for a ring.
Another known method of manufacturing a fibre reinforced metal ring, as disclosed in UK patent Application No. GB2198675A, a continuous helical tape of fibers and a continuous helical tape of metal foil are interleaved. The interleaved helical tapes of fibers and metal foil are pressed axially to consolidate the assembly. This method produced little or no breaking of the fibers.
The present invention seeks to provide a novel method of manufacturing fibre reinforced metal components.
Accordingly the present invention provides a method of manufacturing a fibre reinforced metal component comprising arranging at least one separate piece of metal matrix composite and at least on e piece of unreinforced metal matrix alternately in adjacent abutting relationship to form at least one laminate, the at least one separate piece of metal matrix composite comprises a plurality of undirectionally arranged fibers in a metal matrix, the at least one separate piece of metal matrix composite being arranged such that the fibers embedded in the metal matrix extend in the same directional sense, arranging the at least one laminate of at least one metal matrix composite piece and at least one piece of unreinforced metal matrix between a first metal member and a second metal member to form an assembly, consolidating the assembly to bond the first metal member, the at least one laminate of at least one metal matrix composite and the at least one piece of metal matrix and the second metal member to form a unitary composite component.
Preferably a plurality of separate pieces of metal matrix composite and a plurality of pieces of unreinforced metal matrix are arranged to form at least one laminate.
Preferably the at least one separate piece of metal matrix composite and the at least one piece of unreinforced metal matrix are arranged in a ring, the first metal member and the second metal member are rings.
Preferably a plurality of separate pieces of metal matrix composite and a plurality of pieces of unreinforced metal matrix are arranged in a spiral to form a plurality of laminates.
Alternately a plurality of separate pieces of metal matrix composite and a plurality of pieces of unreinforced metal matrix are arranged in concentric rings to form a plurality of laminates.
The pieces of metal matrix composite may have equal lengths.
The second metal ring is preferably positioned radially outwardly of the at least one laminate of metal matrix composite.
At least one rotor blade may be welded onto the second metal ring by friction welding or electron beam welding.
Preferably the second metal ring is machined to form at least one rotor blade integral with the second metal ring.
Preferably the second metal member is electrochemically machined to form the at least one rotor blade.
The separate pieces of metal matrix composite and the pieces of unreinforced metal matrix may be secured to a continuous backing strip to allow the separate pieces of metal matrix composite and the pieces of unreinforced metal matrix to be wound into a spiral.
The backing strip may comprise unreinforced metal matrix.
Preferably the backing strip comprises a plastic or other suitable material which is subsequently removed.
The first metal member, the second metal member and the metal matrix composite may comprise titanium, titanium aluminide, an alloy of titanium or any suitable metal, alloy or intermetallic which is capable of being bonded.
The fibers may comprise silicon carbide, silicon nitride, boron, alumina or other suitable ceramic fibers.
Preferably the consolidating process comprises hot isostatic pressing.
The consolidating process may alternately comprise differential hot expansion of a first ring inside a suitable low expansion second ring.
The pieces of metal matrix composite and the pieces of metal matrix are preferably arranged on the inner surface of the second metal ring, the first metal ring is moved coaxially into the second metal ring.
The second metal ring preferably has a radially inwardly extending flange at one axial end to locate the pieces of metal matrix composite and the pieces of metal matrix axially.
The first metal ring preferably has a radially outwardly extending flange at one axial end to locate the pieces of metal matrix composite and the pieces of metal matrix axially.